Polydiazaacenes

ABSTRACT

A polymer represented by Formula or structure (I)  
                 
 
wherein at least one of each R, R 1 , R 2 , R 3 , R 4 , R 5 , and R 6  is independently hydrogen, alkyl, aryl, arylalkyl, alkoxy, halogen, cyano, or nitro; x, y, a and b represent the number of groups and rings, respectively; and n represents the number of repeating groups or moieties.

CROSS REFERENCE TO RELATED APPLICATIONS

U.S. Application No. (not yet assigned) (Attorney Docket No.20050024-US-NP), filed concurrently herewith, on FunctionalizedHeteroacenes and Electronic Devices Generated Therefrom, by Yuning Li etal.

U.S. Application No. (not yet assigned) (Attorney Docket No.20050024Q-US-NP), filed concurrently herewith, on FunctionalizedHeteroacenes, by Yuning Li et al.

U.S. Application No. (not yet assigned) (Attorney Docket No.20050471-US-NP), filed concurrently herewith, on Polyacenes andElectronic Devices Generated Therefrom, by Yuning Li et al.

U.S. Application No. (not yet assigned) (Attorney Docket No.20050472-US-NP), filed concurrently herewith, on Heteroacene Polymersand Electronic Devices Generated Therefrom, by Yuning Li et al.

U.S. Application No. (not yet assigned) (Attorney Docket No.20050473-US-NP), filed concurrently herewith, on Ethynylene AcenePolymers and Electronic Devices Generated Therefrom, by Yuning Li et al.

U.S. Application No. (not yet assigned) (Attorney Docket No.20050473Q-US-NP), filed concurrently herewith, on Ethynylene AcenePolymers, by Yuning Li et al.

U.S. Application No. (not yet assigned) (Attorney Docket No.20050474-US-NP), filed concurrently herewith, onPoly[bis(ethynyl)heteroacenes] and Electronic Devices GeneratedTherefrom, by Yuning Li et al.

U.S. Application No. (not yet assigned) (Attorney Docket No.20050539-US-NP), filed concurrently herewith, on Semiconductors andElectronic Devices Generated Therefrom, by Yiliang Wu et al.

U.S. Application No. (not yet assigned) (Attorney Docket No.20050539Q-US-NP), filed concurrently herewith, on SemiconductorPolymers, by Yiliang Wu et al.

U.S. Application No. (not yet assigned) (Attorney Docket No.20050540-US-NP), filed concurrently herewith, on Polydiazaacenes andElectronic Devices Generated Therefrom, by Yiliang Wu et al.

U.S. Application No. (not yet assigned) (Attorney Docket No.20050707-US-NP), filed concurrently herewith, on Poly(alkynylthiophene)sand Electronic Devices Generated Therefrom, by Beng S. Ong et al.

U.S. Application No. (not yet assigned) (Attorney Docket No.20050707Q-US-NP), filed concurrently herewith, onPoly(alkynylthiophene)s, by Beng S. Ong et al.

U.S. Application No. (not yet assigned) (Attorney Docket No.20050711-US-NP), filed concurrently herewith, on Linked ArylaminePolymers and Electronic Devices Generated Therefrom, by Yuning Li et al.

U.S. Application No. (not yet assigned) (Attorney Docket No.20050711Q-US-NP), filed concurrently herewith, on Linked ArylaminePolymers, by Yuning Li et al.

Illustrated in U.S. application Ser. No. 11/011,678 (Attorney Docket No.A3571-US-NP) filed Dec. 14, 2004 relating to indolocarbazole moietiesand thin film transistor devices thereof.

Illustrated in U.S. application Ser. No. 11/167,512 (Attorney Docket No.A3571-US-CIP) filed Jun. 27, 2005 relating to indolocarbazole moietiesand thin film transistor devices thereof.

Illustrated in U.S. Pat. No. 6,770,904 and copending application U.S.application Ser. No. 10/922,662, Publication No. 20050017311 (AttorneyDocket No. A1332-US-CIP), are electronic devices, such as thin filmtransistors containing semiconductor layers of, for example,polythiophenes.

The disclosure of each of the above cross referenced applications andpatent is totally incorporated herein by reference. In aspects of thepresent disclosure, there may be selected the appropriate substituents,such as a suitable hydrocarbon, a heteroatom containing group, hydrogen,halogen, CN, NO₂, rings, number of repeating polymer units, number ofgroups, and the like as illustrated in the copending applications.

The appropriate components, processes thereof and uses thereofillustrated in these copending applications and patent may be selectedfor the present invention in embodiments thereof.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The electronic devices and certain components thereof were supported bya United States Government Cooperative Agreement No. 70NANBOH3033awarded by the National Institute of Standards and Technology (NIST).The United States Government has certain rights relating to the devicesand certain semiconductor components illustrated hereinafter.

BACKGROUND

The present disclosure is generally directed to polymers likepolydiazaacenes, processes of preparation and uses thereof. Morespecifically, the present disclosure in embodiments is directed to novelpolydiazaacenes selected as solution processable and substantiallystable channel semiconductors in organic electronic devices, such asthin film transistors.

There are desired electronic devices, such as thin film transistors,TFTs, fabricated with polydiazaacenes, with excellent solventsolubility, which can be solution processable; and which devices possessmechanical durability and structural flexibility, characteristics whichare desirable for fabricating flexible TFTs on plastic substrates.Flexible TFTs enable the design of electronic devices with structuralflexibility and mechanical durability characteristics. The use ofplastic substrates together with the polydiazaacene can transform thetraditionally rigid silicon TFT into a mechanically more durable andstructurally flexible TFT design. This can be of particular value tolarge area devices such as large-area image sensors, electronic paper,and other display media. Also, the selection of polydiazaacenes TFTs forintegrated circuit logic elements for low end microelectronics, such assmart cards, radio frequency identification (RFID) tags, andmemory/storage devices, is believed to enhance their mechanicaldurability, and thus their useful life span.

A number of semiconductor materials are not, it is believed, stable whenexposed to air as they become oxidatively doped by ambient oxygenresulting in increased conductivity. The result is large off-current andthus a low current on/off ratio for the devices fabricated from thesematerials. Accordingly, with many of these materials, rigorousprecautions are usually undertaken during materials processing anddevice fabrication to exclude environmental oxygen to avoid or minimizeoxidative doping. These precautionary measures increase the cost ofmanufacturing therefore offsetting the appeal of certain semiconductorTFTs as an economical alternative to amorphous silicon technology,particularly for large area devices. These and other disadvantages areavoided or minimized in embodiments of the present disclosure.

TFTs fabricated from polydiazaacenes may be functionally andstructurally more desirable than conventional silicon technology in thatthey may offer mechanical durability, structural flexibility, and thepotential of being able to be incorporated directly onto the activemedia of the devices, thus enhancing device compactness fortransportability.

REFERENCES

Regioregular polyhexylthiophenes undergo rapid photo oxidativedegradation under ambient conditions, while the known polytriarylaminespossess some stability when exposed to air, however, these amines arebelieved to possess low field effect mobilities, in some instances,disadvantages avoided, or minimized with the polydiazaacenes of thepresent disclosure.

Also, acenes, such as pentacene, and heteroacenes are known to possessacceptable high field effect mobility when used as channelsemiconductors in TFTs. However, these materials are rapidly oxidizedby, for example, atmospheric oxygen under light, and such acenes are notconsidered processable at ambient conditions. Furthermore, when selectedfor TFTs a number of known acenes have poor thin film formationcharacteristics and are substantially insoluble thus they areessentially nonsolution processable; accordingly, such acenes have beenprocessed by vacuum deposition methods that result in high productioncosts, eliminated or minimized with the TFTs generated with thepolydiazaacenes illustrated herein.

A number of organic semiconductor materials has been described for usein field effect TFTs, which materials include organic small moleculessuch as pentacene, see for example D. J. Gundlach et al., “Pentaceneorganic thin film transistors—molecular ordering and mobility”, IEEEElectron Device Lett., Vol. 18, p. 87 (1997); oligomers such assexithiophenes or their variants, see for example reference F. Garnieret al., “Molecular engineering of organic semiconductors: Design ofself-assembly properties in conjugated thiophene oligomers”, J. Amer.Chem. Soc., Vol. 115, p. 8716 (1993), and poly(3-alkylthiophene), seefor example, the reference Z. Bao et al., “Soluble and processableregioregular poly(3-hexylthiophene) for field-effect thin filmtransistor application with high mobility”, Appl. Phys. Lett. Vol. 69,p4108 (1996). Although organic material based TFTs generally providelower performance characteristics than their conventional siliconcounterparts, such as silicon crystals or polysilicon TFTs, they may benonetheless sufficiently useful for applications in areas where highmobility is not required.

Illustrated in Huang, D. H., et al, Chem. Mater. 2004, 16, 1298-1303,are, for example, LEDS and field effect transistors based on certainphenothiaazines like poly(10-(2-ethylhexyl)phenothiaazine).

Illustrated in Zhu, Y., et al, Macromolecules 2005, 38, 7983-7991, are,for example, semiconductors based on phenoxazine conjugated polymerslike poly(10-hexylphenoxazine).

A number of known small molecule or oligomer-based TFT devices rely ondifficult vacuum deposition techniques for fabrication. Vacuumdeposition is selected primarily because the small molecular materialsare either insoluble or their solution processing by spin coating,solution casting, or stamp printing do not generally provide uniformthin films.

Further, vacuum deposition may also involve the difficulty of achievingconsistent thin film quality for large area format. Polymer TFTs, suchas those fabricated from regioregular components, of, for example,regioregular poly(3-alkylthiophene-2,5-diyl) by solution processes,while offering some mobility, suffer from their propensity towardsoxidative doping in air. For practical low cost TFT design, it istherefore of value to have a semiconductor material that is both stableand solution processable, and where its performance is not adverselyaffected by ambient oxygen, for example, TFTs generated withpoly(3-alkylthiophene-2,5-diyl) are sensitive to air. The TFTsfabricated from these materials in ambient conditions generally exhibitlarge off-current, very low current on/off ratios, and their performancecharacteristics degrade rapidly.

Additional references that may be of interest include U.S. Pat. Nos.6,150,191; 6,107,117; 5,969,376; 5,619,357, and 5,777,070.

BRIEF DESCRIPTION OF THE FIGURES

Illustrated in FIGS. 1 to 4 are various representative embodiments ofthe present disclosure, and wherein polydiazaacenes, and morespecifically, the polydiazaacenes wherein at least one of R₁ and R₂ isof dodecylphenyl, and n is about 50, are selected as the channel orsemiconductor material in thin film transistor (TFT) configurations.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

It is a feature of the present disclosure to provide semiconductorpolydiazaacenes, which are useful for microelectronic deviceapplications, such as TFT devices.

It is another feature of the present disclosure to providepolydiazaacenes with a band gap of from about 1.5 eV to about 3 eV asdetermined from the absorption spectra of thin films thereof, and whichpolydiazaacenes are suitable for use as TFT semiconductor channel layermaterials and mobilities of from about 10⁻³ to about 10⁻¹.

In yet a further feature of the present disclosure there are providednovel polydiazaacenes which are useful as microelectronic components,and which polydiazaacenes possess solubility of, for example, at leastabout 0.1 percent to about 95 by weight in common organic solvents, suchas methylene chloride, tetrahydrofuran, toluene, xylene, mesitylene,chlorobenzene, dichlorobenzene, and the like, and thus thesepolydiazaacenes can be economically fabricated by liquid processes suchas spin coating, screen printing, stamp printing, dip coating, solutioncasting, jet printing, and the like.

Another feature of the present disclosure resides in providingelectronic devices, such as TFTs, with a polydiazaacene channel layer,and which layer has a conductivity of from about 10⁻⁴ to about 10⁻⁹ S/cm(Siemens/centimeter).

Also, in yet another feature of the present disclosure there areprovided novel polydiazaacenes and devices thereof, and which devicesexhibit enhanced resistance to the adverse effects of oxygen, that is,these devices exhibit relatively high current on/off ratios, and theirperformance does not substantially degrade as rapidly as similar devicesfabricated with regioregular poly(3-alkylthiophene-3,5-diyl) or withacenes.

Additionally, in a further feature of the present disclosure there isprovided a class of novel polydiazaacenes including those with twotertiary amine groups, which can stabilize radical cation,s and withunique structural features which permit molecular self-alignment underappropriate processing conditions, and which structural features alsoenhance the stability of device performance. Proper molecular alignmentcan permit higher molecular structural order in thin films, which can beimportant to efficient charge carrier transport, thus higher electricalperformance.

There are disclosed in embodiments, polydiazaacenes and electronicdevices thereof. In embodiments, polydiazaacene refers, for example, topolymer containing diazaacene structures. More specifically, the presentdisclosure relates to polydiazaacenes illustrated by or encompassed byFormula (I)

wherein, for example, x and y represent the number of R substituents of,for example, independently from 0 to about 3; a and b represent thenumber of the rings of, for example, from 0 to about 3; each R, R₁, R₂,R₃, R₄, R₅ and R₆ is independently hydrogen, alkyl, aryl, alkoxy,arylalkyl, alkyl substituted aryls, halogen, cyano, nitro and the like;and mixtures thereof; and n represents the number of repeating units,such as for example, n is a number of from about 2 to about 5,000, andmore specifically, from about 2 to about 500, or from about 10 to about100.

The number average molecular weight (M_(n)) of the polydiazaacenes canbe, for example, from about 500 to about 300,000, including from about500 to about 100,000, and the weight average molecular weight (M_(w))thereof can be from about 600 to about 500,000, including from about 600to about 200,000, both as measured by gel permeation chromatographyusing polystyrene standards.

In embodiments, specific classes of polydiazaacenes are represented bythe following formulas

wherein each R and n is as illustrated herein, and more specifically,wherein each R₁ and R₂ is independently hydrogen, alkyl, aryl, alkoxy,arylalkyl, alkyl substituted aryls, and the like; and mixtures thereof;and n represents the number of repeating units, such as for example, nis a number of from about 2 to about 5,000, and more specifically, fromabout 2 to about 1,000 or from about 50 to about 700. In embodiments, R₁and R₂ are alkyl, arylalkyl, and alkyl substituted aryls. Examples ofspecific R₁ and R₂ are alkyl with from about 5 to about 25 carbon atomsof, for example, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl,dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl andoctadecyl; arylalkyl with from about 7 to about 26 carbon atoms of, forexample, methylphenyl(tolyl), ethylphenyl, propylphenyl, butylphenyl,pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl,decylphenyl, undecylphenyl, dodecylphenyl, tridecylphenyl,tetradecylphenyl, pentadecylphenyl, hexadecylphenyl, heptadecylphenyl,and octadecylphenyl; or aryl with from about 6 to about 48 carbon atoms,such as phenyl.

In embodiments there are disclosed processes for the preparation ofpolydiazaacenes in accordance, for example, with the following reactionscheme (Scheme 1), and more specifically, where polydiazaacenes can beprepared by utilizing a dehalogenative coupling reaction ofdihalogenated diazaacenes.

In Scheme 1, x and y represent the number of R substituents, each ofthem being, for example, independently from 0 to about 3; a and brepresent the number of the rings, each of them being, for example, from0 to about 3; each R, R₁, R₂, R₃, R₄, R₅ and R₆ is independentlyhydrogen, alkyl, aryl, alkoxy, arylalkyl, alkyl substituted aryls,halogen, cyano, nitro and the like, and mixtures thereof; and nrepresents the number of repeating units.

More specifically, the process for the preparation of thepolydiazaacenes can be accomplished by, for example, the dehalogenativecoupling polymerization of dichloro-diazaacenes in the presence of zinc,nickel(II) chloride, 2,2′-dipyridil, and triphenylphosphine indimethylacetamide (DMAc) at an elevated temperature of, for example,about 70° C. to about 90° C., and more specifically, about 80° C. for asuitable period of time, like 24 hours, as illustrated in Scheme 2;wherein the monomer dichlordiazaacenes can be effectively achievedthrough a condensation reaction between a 1,2-aromatic diamine and a1,2-aromatic diol at elevated temperatures, for example, from about 160°C. to about 180° C., for a suitable time like from about 30 to about 60minutes, followed by reacting the product obtained with an aryliodideusing excess copper and a catalytic amount of an 18-crown-6 ether inrefluxing 1,2-dichlorobenzene for about 24 hours (Scheme 2).

and wherein i) is accomplished by heating at elevated temperatures, forexample, at 180° C., for a suitable time period like from about 30 toabout 60 minutes; ii) followed by adding copper powder, 18-crown-6ether, 12-dichlorobenzene, and refluxing for a suitable period, such asabout 24 hours or other suitable time; iii) adding Zn, NiCl₂,2,2′-bipyridil, PPh₃, DMAc, and heating at elevated temperature of, forexample, about 80° C.

Examples of each of the R, R₁, R₂, R₃, R₄, R₅ and R₆ groups for thepolydiazaacenes are as illustrated herein, and include alkoxy and alkylwith, for example, from about 1 to about 25, including from about 1 toabout 18 carbon atoms (included throughout are numbers within the range,for example 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 and 18),and further including from about 6 to about 16 carbon atoms, such asmethyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl,decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl,heptadecyl, octadecyl, nonadecyl, or eicosanyl, isomeric forms thereof,mixtures thereof, and the like, and the corresponding alkoxides, such aspropoxy, butoxy, octoxy, and the like; alkylaryl with from about 7 toabout 49 carbon atoms, from about 7 to about 37 carbon atoms, or fromabout 13 to about 25 carbon atoms, such as methylphenyl, octylphenyl,dodecylphenyl, and substituted phenyls; aryl with from 6 to about 48carbon atoms, and more specifically, with from about 6 to about 18carbon atoms, such as phenyl, biphenyl; and halogen of chloride,bromide, fluoride or iodide.

Specific Illustrative Polymer Examples are

wherein R₁ is alkyl, R₂ is alkyl, and n is a number of from 2 to about100.

The polydiazaacenes in embodiments are soluble or substantially solublein common coating solvents, for example, in embodiments they possess asolubility of at least about 0.1 percent to about 95 percent by weight,and more specifically, from about 0.5 percent to about 10 percent byweight in such solvents as methylene chloride, 1,2-dichloroethane,tetrahydrofuran, toluene, xylene, mesitylene, chlorobenzene,dichlorobenzene, and the like. Moreover, the polydiazaacenes of thepresent disclosure in embodiments, when fabricated as semiconductorchannel layers in TFT devices, provide a stable conductivity of, forexample, from about 10⁻⁹ S/cm to about 10⁻⁴ S/cm, and more specifically,from about 10⁻⁸ S/cm to about 10⁻⁵ S/cm as determined by conventionalfour-probe conductivity measurements.

It is believed that the polydiazaacenes when fabricated from solutionsas thin films of, for example, from about 10 nanometers to about 500nanometers, or from about 50 to about 300 nanometers in thickness, aremore stable in ambient conditions than similar devices fabricated fromacenes like pentacene and its derivatives or from polyacenes. Whenunprotected, the aforementioned polydiazaacenes materials and devicesare generally stable for a number of weeks rather than days or hours asis the situation with poly(3-alkylthiophene-2,5-diyl) after exposure toambient oxygen, thus the devices fabricated from the polydiazaacenes inembodiments of the present disclosure can provide higher current on/offratios, and their performance characteristics do not substantiallychange as rapidly as pentacene or than poly(3-alkylthiophene-2,5-diyl)when no rigorous procedural precautions have been taken to excludeambient oxygen during material preparation, device fabrication, andevaluation. The polydiazaacenes stability of the present disclosure inembodiments against oxidative doping, particularly for low cost devicemanufacturing, does not usually have to be handled in an inertatmosphere, and the processes thereof are, therefore, simpler and morecost effective, and the fabrication thereof can be applied to largescale production processes.

Aspects of the present disclosure relate to a polymer represented byFormula or structure (I)

wherein at least one of each R, R₁, R₂, R₃, R₄, R₅ and R₆ isindependently hydrogen, alkyl, aryl, arylalkyl, alkoxy, halogen, cyano,or nitro; x, y, a and b represent the number of groups and rings,respectively; and n represents the number of repeating groups ormoieties; a polymer represented by the following formulas/structures

wherein at least one of R₁ and R₂ are independently alkyl with fromabout 5 to about 20 carbon atoms; aryl with from about 6 to about 36carbon atoms, or alkylaryl with from about 7 to about 37 carbon atoms;and n is from 2 to about 100; a polydiazaacene of the followingformulas/structures

wherein at least one of R₁ and R₂ is a suitable hydrocarbon; and n isfrom 2 to about 2,000; a TFT device wherein the substrate is a plasticsheet of a polyester, a polycarbonate, or a polyimide; the gate sourceand drain electrodes are each independently comprised of gold, nickel,aluminum, platinum, indium titanium oxide, or a conductive polymer, andthe gate dielectric is a dielectric layer comprised of silicon nitrideor silicon oxide; a TFT device wherein the substrate is glass or aplastic sheet; said gate, source and drain electrodes are each comprisedof gold, and the gate dielectric layer is comprised of the organicpolymer poly(methacrylate) or poly(vinyl phenol); a device wherein thepolydiazaacene layer is formed by solution processes of spin coating,stamp printing, screen printing, or jet printing; a device wherein thegate, source and drain electrodes, the gate dielectric, andsemiconductor layers are formed by solution processes of spin coating,solution casting, stamp printing, screen printing, or jet printing; anda TFT device wherein the substrate is a plastic sheet of a polyester, apolycarbonate, or a polyimide, and the gate, source and drain electrodesare fabricated from the organic conductive polymer polystyrenesulfonate-doped poly(3,4-ethylene dioxythiophene), or from a conductiveink/paste compound of a colloidal dispersion of silver in a polymerbinder, and the gate dielectric layer is organic polymer or inorganicoxide particle-polymer composite; device or devices include electronicdevices such as TFTs.

DETAILED DESCRIPTION OF THE FIGURES

In FIG. 1 there is schematically illustrated a TFT configuration 10comprised of a substrate 16, in contact therewith a metal contact 18(gate electrode), and a layer of an insulating dielectric layer 14 withthe gate electrode having a portion thereof or the entire gate incontact with the dielectric layer 14 with the gate electrode having aportion thereof or the entire gate in contact with the dielectric layer14 on top of which layer 14 two metal contacts, 20 and 22 (source anddrain electrodes), are deposited. Over and between the metal contacts 20and 22 is the Formula (I) or Formula (4) polydiazaacene layer 12 whereinR₁ and R₂ are C₈H₁₇ phenyl. The gate electrode can be included in thesubstrate, in the dielectric layer, and the like throughout.

FIG. 2 schematically illustrates another TFT configuration 30 comprisedof a substrate 36, a gate electrode 38, a source electrode 40, and adrain electrode 42, an insulating dielectric layer 34, and apolydiazaacene semiconductor layer 32 of Formula (I) of FIG. 1.

FIG. 3 schematically illustrates a further TFT configuration 50comprised of a heavily n-doped silicon wafer 56, which can act as a gateelectrode, a thermally grown silicon oxide dielectric layer 54, apolydiazaacene semiconductor layer 52 of Formula (I) or Formula (4) ofFIG. 1, on top of which are deposited a source electrode 60 and a drainelectrode 62; and a gate electrode contact 64.

FIG. 4 schematically illustrates a TFT configuration 70 comprised ofsubstrate 76, a gate electrode 78, a source electrode 80, a drainelectrode 82, a polydiazaacene semiconductor layer 72 of Formula (I) orFormula (4) of FIG. 1, and an insulating dielectric layer 74.

Also, other devices not disclosed, especially TFT devices, areenvisioned, reference for example known TFT devices.

In some embodiments of the present disclosure, an optional protectinglayer may be incorporated on top of each of the transistorconfigurations of FIGS. 1, 2, 3 and 4. For the TFT configuration of FIG.4, the insulating dielectric layer 74 may also function as a protectinglayer.

In embodiments and with further reference to the present disclosure andthe Figures, the substrate layer may generally be a silicon materialinclusive of various appropriate forms of silicon, a glass plate, aplastic film or a sheet, and the like depending on the intendedapplications. For structurally flexible devices, a plastic substrate,such as for example polyester, polycarbonate, polyimide sheets, and thelike, may be selected. The thickness of the substrate may be, forexample, from about 10 micrometers to over 10 millimeters with aspecific thickness being from about 50 to about 100 micrometers,especially for a flexible plastic substrate and from about 1 to about 10millimeters for a rigid substrate such as glass or silicon.

The insulating dielectric layer, which can separate the gate electrodefrom the source and drain electrodes, and in contact with thesemiconductor layer, can generally be an inorganic material film, anorganic polymer film, or an organic-inorganic composite film. Thethickness of the dielectric layer is, for example, from about 10nanometers to about 1 micrometer with a more specific thickness beingabout 100 nanometers to about 500 nanometers. Illustrative examples ofinorganic materials suitable as the dielectric layer include siliconoxide, silicon nitride, aluminum oxide, barium titanate, bariumzirconate titanate, and the like; illustrative examples of organicpolymers for the dielectric layer include polyesters, polycarbonates,poly(vinyl phenol), polyimides, polystyrene, poly(methacrylate)s,poly(acrylate)s, epoxy resin, and the like; and illustrative examples ofinorganic-organic composite materials include nanosized metal oxideparticles dispersed in polymers, such as polyester, polyimide, epoxyresin and the like. The insulating dielectric layer is generally of athickness of from about 50 nanometers to about 500 nanometers dependingon the dielectric constant of the dielectric material used. Morespecifically, the dielectric material has a dielectric constant of, forexample, at least about 3, thus a suitable dielectric thickness of about300 nanometers can provide a desirable capacitance, for example, ofabout 10⁻⁹ to about 10⁻⁷ F/cm².

Situated, for example, between and in contact with the dielectric layerand the source/drain electrodes is the active semiconductor layercomprised of the polydiazaacene illustrated herein, and wherein thethickness of this layer is generally, for example, about 10 nanometersto about 1 micrometer, or about 40 to about 100 nanometers. This layercan generally be fabricated by solution processes such as spin coating,casting, screen, stamp, or jet printing of a solution of thepolydiazaacenes of the present disclosure.

The gate electrode can be a thin metal film, a conducting polymer film,a conducting film generated from a conducting ink or paste, or thesubstrate itself (for example heavily doped silicon). Examples of gateelectrode materials include, but are not limited to aluminum, gold,chromium, indium tin oxide, conducting polymers, such as polystyrenesulfonate-doped poly(3,4-ethylenedioxythiophene) (PSS/PEDOT), aconducting ink/paste comprised of carbon black/graphite or colloidalsilver dispersion contained in a polymer binder, such as Electrodagavailable from Acheson Colloids Company, and silver filled electricallyconductive thermoplastic ink available from Noelle Industries, and thelike. The gate layer can be prepared by vacuum evaporation, sputteringof metals or conductive metal oxides, coating from conducting polymersolutions or conducting inks or dispersions by spin coating, casting orprinting. The thickness of the gate electrode layer is, for example,from about 10 nanometers to about 10 micrometers, and a specificthickness is, for example, from about 10 to about 200 nanometers formetal films and about 1 to about 10 micrometers for polymer conductors.

The source and drain electrode layer can be fabricated from materialswhich provide a low resistance ohmic contact to the semiconductor layer.Typical materials suitable for use as source and drain electrodesinclude those of the gate electrode materials, such as gold, nickel,aluminum, platinum, conducting polymers, and conducting inks. Typicalthickness of this layer is, for example, from about 40 nanometers toabout 1 micrometer with the more specific thickness being about 100 toabout 400 nanometers. The TFT devices contain a semiconductor channelwith a width W and length L. The semiconductor channel width may be, forexample, from about 10 micrometers to about 5 millimeters, with aspecific channel width being about 100 micrometers to about 1millimeter. The semiconductor channel length may be, for example, fromabout 1 micrometer to about 1 millimeter with a more specific channellength being from about 5 micrometers to about 100 micrometers.

The source electrode is grounded and a bias voltage of generally, forexample, about 0 volt to about −80 volts is applied to the drainelectrode to collect the charge carriers transported across thesemiconductor channel when a voltage of generally, for example, about+10 volts to about −80 volts is applied to the gate electrode.

Although not desiring to be limited by theory, it is believed that thediaza groups function primarily to minimize or avoid instability becauseof exposure to oxygen, and thus increase the oxidative stability of thepolydiazaacene in solution under ambient conditions, and the R and R₁through R₆ substituents, such as alkyl, permit the solubility of thesepolymers in common solvents, such as ethylene chloride.

The claims, as originally presented and as they may be amended,encompass variations, alternatives, modifications, improvements,equivalents, and substantial equivalents of the embodiments andteachings disclosed herein, including those that are presentlyunforeseen or unappreciated, and that, for example, may arise fromapplicants/patentees and others. Unless specifically recited in a claim,steps or components of claims should not be implied or imported from thespecification or any other claims as to any particular order, number,position, size, shape, angle, color, or material.

1. A polymer represented by Formula or structure (I)

wherein at least one of each R, R₁, R₂, R₃, R₄, R₅, and R₆ isindependently hydrogen, alkyl, aryl, arylalkyl, alkoxy, halogen, cyano,or nitro; x, y, a and b represent the number of groups and rings,respectively; and n represents the number of repeating groups ormoieties.
 2. A polymer in accordance with claim 1 wherein n represents anumber of from about 2 to about 5,000.
 3. A polymer in accordance withclaim 1 wherein n represents a number of from about 100 to about 1,000,or from about 10 to about
 200. 4. A polymer in accordance with claim 1wherein n represents a number of from about 20 to about 100
 5. A polymerin accordance with claim 1 wherein at least one of each R, R₁, R₂, R₃,R₄, R₅ and R₆ is alkyl.
 6. A polymer in accordance with claim 1 whereinat least one of each R, R₁, R₂, R₃, R₄, R₅ and R₆ is aryl.
 7. A polymerin accordance with claim 1 wherein x and y are independently from 0 toabout
 3. 8. A polymer in accordance with claim 1 wherein a and b areindependently from 0 to about
 3. 9. A polymer in accordance with claim 1wherein at least one of each R, R₁, R₂, R₃, R₄, R₅ and R₆ is nitro orcyano.
 10. A polymer in accordance with claim 1 wherein at least one ofR, R₁, R₂, R₃, R₄, R₅ and R₆ is independently methyl, ethyl, propyl,butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl,tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl,nonadecyl, eicosanyl, phenyl, octylphenyl, dodecylphenyl, octoxyphenyl,or dodecyloxyphenyl.
 11. A polymer represented by the followingformulas/structures

wherein at least one of R₁ and R₂ are independently alkyl with fromabout 5 to about 20 carbon atoms; aryl with from about 6 to about 36carbon atoms, or alkylaryl with from about 7 to about 37 carbon atoms;and n is from 2 to about
 100. 12. A polymer in accordance with claim 11wherein said alkyl is pentyl, hexyl, heptyl, octyl, nonyl, decyl,undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl,heptadecyl or octadecyl.
 13. A polymer in accordance with claim 11wherein at least one of each R, R₁, R₂, R₃, R₄, R₅ and R₆ isindependently aryl.
 14. A polymer in accordance with claim 1 wherein atleast one of R, R₁, R₂, R₃, R₄, R₅ and R₆ is arylalkyl.
 15. A polymer inaccordance with claim 1 wherein alkyl contains from about 1 to about 25carbon atoms.
 16. A polymer in accordance with claim 1 wherein arylcontains from 6 to about 48 carbon atoms.
 17. A polymer in accordancewith claim 1 wherein aryl contains from 6 to about 18 carbon atoms. 18.A polymer in accordance with claim 1 wherein alkyl is butyl, pentyl,hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl,tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, oreicosanyl; and n is from about 20 to about
 75. 19. A polymer inaccordance with claim 1 of the following alternative formulas/structures

wherein R₁ and R₂ are independently alkyl, aryl, or arylalkyl with fromabout 7 to about 26 carbon atoms; and n is from 2 to about
 100. 20. Apolymer in accordance with claim 19 wherein arylalkyl is methylphenyl,ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl,heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl,dodecylphenyl, tridecylphenyl, tetradecylphenyl, pentadecylphenyl,hexadecylphenyl, heptadecylphenyl, or octadecylphenyl.
 21. Apolydiazaacene of the following formulas/structures

wherein at least one of R₁ and R₂ is a suitable hydrocarbon; and n isfrom 2 to about 2,000.
 22. A polymer in accordance with claim 1 of thefollowing formula/structure

wherein R₁ and R₂ are alkyl with from about 12 to about 20 carbon atoms;and n is from 10 to about 2,000.
 23. A polymer in accordance with claim11 wherein R₁ and R₂ are dodecylphenyl.